Method of inking



D. 1, 1942. A H 2,303,355

Patented Dec. 1, 1942 seine METHOD OF INKING Adalbert B. Guth, Oak Park,Ill., assignor to Ditto, Incorporated, Chicago, 111., a corporation ofWest Virginia Application April '7, 1941, Serial No. 387,121

4 Claims.

The present invention relates to printing apparatus and particularly toa novel printing plate and the inking thereof.

.Heretofore, insofar as I am aware, it has been customary in thepreparation of printing plates and in the inking thereof to roll theinking roller across the printing plate, the surface of the printingplate being so prepared that first, raised por- -.tions are to be inked,in which case the depressed portions are not contacted by the ink or areink repellent; second, depressed portions are to be inked, in which casethe depressions are filled with ink and the raised portions are wipedclear or are ink repellent, and third, the distinction between the inkreceiving and non-ink receiving parts of the plate are purelyaccomplished by making the printing surface ink repellent or inkattracting, the parts to be printed in this case being ink attracting.

In accordance with the present invention I provide a printing plate, thesurface of which has the portions which are to receive the greatestamount of ink higher than the other portions. The material used is suchthat the printing plate is resilient and the higher portions are moreresilient than the lower portions, that is, softer and hence more easilydepressed. I combine this printing plate with an inking rollercombination wherein the inking roller is rotated in such direction thatthe surface thereof first en- 1 gaging the plate is moving in the samedirection as the roller moves across the plate. In other words, theroller surface is wiping the plate surface in the same direction thatthe roller is traversing the plate. In order that the invention may bemore clearly understood the printing plate and roller combination isillustrated in the accompanying drawin wherein- Fig. 1 is a diagrammaticsketch showing a cleaning roller, an inking roller and an oscillatingtransfer roller in connection with a printing plate and a platen or bedupon which the printing plate is fixed; and

Fig. 2 is an enlarged fragmentary view illustrating more in detail theoperation of inking the printing plate.

Referring now in detail to the drawing, the numeral 5 indicates a bedplate of a printing machine upon which a printing plate 6 is mounted.The printing plate 6 has its printing surface made up of raised portionsI and depressed portions 8 which in accordance with well known practicedelineate the pattern to be printed.

The printing plate is inked by means of an inking roller 9 which formspart of an inking roller tions of the plate.

assembly composed of a cleaning roller If), an

oscillating or ink transfer roller I l and the usual mechanism by whichink is fed to the transfer roller for spreading on the inking rolleritself.

It will be understood that suitable drive means are provided forrotating the several rollers and for causing the roller assembly totraverse the bed plate and the printing plate mounted thereon. Inaccordance with my invention I rotate the inking roller so that thesurface thereof engaging the printing plate is wiping across theprinting plate. In other words, as the roller advances, the surfacethereof in engagement with the printing plate rotates in the samedirection as the roller advances. The ink is thus being wiped off ontothe printing plate.

The printing plate itself is preferably composed of a colloidal type ofmaterial such as is used in collotype printing. My plate however differsfrom the usual collotype plate because it is resilient and is sodeveloped that the higher portions are softer or more yielding than thedeeper por- All portions are much the same in that none of them is inkrepellent.

In the inking operation the inking roller is pressed down on theprinting plate with sufficient pressure to flatten the raised portionssubstan-' tially so that in advance of the inking roller and to the rearof it these portions bulge up slightly as shown in Fig. 2 of thedrawing. I find that by this combination of printing plate and inkingroller I pile up a greater volume of ink upon the higher portions of theplate than upon the lower portions. This appears to be due to the factthat the higher portions maintain wiping contact with the inking rollerfor a greater peripheral distance than the valleys or lower portions ofthe plate. Those parts of the printing plate which are in greatestrelief will print darkest upon a copy sheet, while those parts which areless in relief will print lightly or not at all, depending upon thepressure that is applied by the inking roller. The ink of course must beof such consistency that it will not run from the higher to the lowerportions of the plate.

From the foregoing description it is believed that the nature of myinvention will be readily apparent to those skilled in this art. Havingthus described my invention what I claim as new and desire to secure byLetters Patent is:

1. A method of inking a printing plate having a printing part comprisingresilient ink receiving portions at different levels arranged to formthe printing image, said method comprising pressing an ink coated rolleragainst the surfaces of said portions and thereby compressing the higherlevel portions more than the lower level portions and causing the rollerto traverse the printing plate and simultaneously rotating the roller ina direction to wipe the ink it carries onto the printing portions asthey emerge from beneath the roller.

2. A method of inking a printing plate having a printing part comprisingresilient ink receiving portions at different levels arranged to formthe printing image, said method comprising pressing an ink coated rolleragainst the surfaces of said portions and thereby compressing the higherlevel portions more than the lower level portions and causing the rollerto traverse the printing plate and simultaneously rotating the roller togive it a higher surface speed than the speed at which it advancesacross the printing surfaceand in a I direction to wipe the ink itcarries onto the printprinting part comprising resilient ink receivingportions at different levels arranged to form the printing image, saidmethod comprising pressing an ink coated roller against the surfaces ofsaid portions with sufiicient pressure to bring all said portions tosubstantially a common level as they pass under the roller and rotatingthe roller in a direction to wipe the ink from the roller onto theprinting surface as the surface emerges from beneath the roller.

4. The method of coating a resilient member having its surface made upof hills and valleys so that the higher portions receive the thickercoatings comprising the traversing of said surface by a coating memberhaving a coating material thereon, pressing the coating member againstthe surface to flatten the hills and advancing the coated surface ofsaid coating member in a direction to wipe the coating thereon onto thesurfaces of said hills and valleys as said surfaces emerge from beneaththe coating member.

